1. Field of the Invention
The present invention generally relates to connectors. More specifically, the present invention relates to a connector, such as a balanced transmission connector, to be engaged with and connected to an opponent connector.
2. Description of the Related Art
As ways for transmitting data, there are a normal transmission type and a balanced transmission type. In the normal transmission type, a single electric wire is used for every data stream. In the balanced transmission type, two electric wires which form a couple for every data stream are used so that a positive signal and a negative signal having the same size as that of the positive signal but having a different direction from that of the positive signal are simultaneously transmitted. The balanced transmission type, compared to the normal transmission type, has an advantage in that there may not be noise influence. Accordingly, the balanced transmission type has been widely used in fields where signals are transmitted at high speed.
FIG. 1 is a schematic perspective view of a related art balanced transmission connector device. FIG. 2 is a schematic view showing structures of surfaces facing each other of a plug connector 2 and a jack connector 3.
A balanced transmission connector device 1 includes the plug connector 2 and the jack connector 3. The plug connector 2 is attached to a back plane (outside board) 4. The jack connector 3 is mounted on a daughter board (outside board) 5. The plug connector 2 and the jack connector 3 are connected to each other so that the back plane 4 and the daughter board 5 are electrically connected to each other by the connector device 1. See, for example, Japanese Laid-Open Patent Application Publication No. 5-275139.
As shown in FIG. 1 and FIG. 2, the plug connector 2 includes plural signal contact pairs 12, plural ground contacts 18, and a U-shaped insulation housing 6. The ground contact 18 has a reverse L-shaped configuration. A ground contact 18 is provided for every signal contact pair 12. The insulation housing 6 is configured to support plural signal contact pairs 12 and plural ground contacts 18.
The signal contact pairs 12 are placed side by side in a row direction (X1-X2 direction) and a line direction (Y1-Y2 direction). Each of the signal contact pairs 12 is formed by signal contacts 14 and 16. The signal contacts 14 and 16 are configured to transmit signals having positive and negative symmetric waveforms. The signal contacts 14 and 16 are arranged in the row direction (X1-X2 direction).
Each of the ground contacts 18 includes a horizontal plate part 18-1 and a vertical plate part 18-2. Each of the ground contacts 18 is configured to cover a Y1 side and an X2 side of the corresponding signal contact pair 12. The horizontal plate part 18-1 extends to a rear side of the housing 6 so as to work as a terminal part.
The jack connector 3, as shown in FIG. 1 and FIG. 2, includes an insulation housing 7, plural modules 8, and plural ground plates (shield plates) 9.
The insulation housing 7 includes openings 74 and 76 and a reverse L-shaped slit 78 corresponding to the ground contact 18 of the plug connector 2. The openings 74 and 76 correspond to the signal contacts 14 and 16 of the plug connector 2.
The modules 8 are placed side by side in the line direction (Y1-Y2 direction). Each of the modules 8 includes four signal contact pairs 22. The signal contact pairs 22 are placed side by side in the row direction (X1-X2 direction). Each of the signal contact pairs 22 includes signal contacts 24 and 26. The signal contacts 24 and 26 are configured to transmit signals having positive and negative symmetric waveforms. The signal contact pairs 24 and 26 are placed side by side in the row direction (X1-X2 direction).
The ground plates 9 are arranged, one by one, between neighboring modules 8.
FIG. 3 is a cross-sectional view of an electrical connecting part of the plug connector 2 and the jack connector 3.
The housing 7 (see FIG. 2) is engaged with the housing 6 (see FIG. 3) and the signal contacts 14 and 16 are inserted in the housing 6 via the openings 74 and 76 and come in contact with the signal contacts 24 and 26, respectively, so that the plug connector 2 and the jack connector 3 are electrically connected to each other.
The ground contact 18 is inserted in the housing 6 via the slit 76. The vertical plate part 18-2 is arranged at a Y1 side of the electrical connection part of the signal contact pair 12 and the signal contact pair 22. The horizontal plate part 18-1 is arranged at an X2 side of the electrical connection part of the signal contact pair 12 and the signal contact pair 22.
Under this structure, the ground contact 18 or the ground plate 9 is arranged between the neighboring signal contacts at the connection part of the plug connector 2 and the jack connector 3. Accordingly, it is possible to prevent cross-talk between neighboring signals and to transmit the signals at high speed.
However, in the structure suggested in Japanese Laid-Open Patent Application Publication No. 5-275139, when the plug connector 2 and the jack connector 3 are connected to each other, the ground contact 18 and the ground plate 9 do not come in contact with each other. Accordingly, a head end side (Z1 side) of the ground contact 18 or a head end side (Z2 side) of the ground plate 9 is a stub of the transmission path. Therefore, an effect of a ground against the high frequency signal is weak and ground potential may fluctuate.